I think you are spot on.It is interesting to note that, in the fifties and sixties, there wasn't much antipathy toward nylon or polyester. In many of these older adverts, the makers of the clothes seem to sing the merits of 100% dacron and trevira and orlon and other variants of these artificial fibres, along with earlier versions like nylon or acrylic, perhaps made through somewhat different processes (I think that was the case, I am no chemist).
So maybe it took some time and experience with these materials to realize that they were not quite as good as natural fibres -- breathability, comfort, aesthetics and so on. Then, of course, they started blending them with natural fibres in different proportions, and that was much better in terms of looks and comfort.
When I was living in India, the overwhelmingly common choice of fabric for shirts and trousers was either terycotton or terywool, a mixture of terylene with those natural fibres. Resistance to wrinkles was the main advantage cited by most people in selecting these types of cloth for their shirts and trousers. I have no idea what the fashion is now for materials. There is widespread use of ready-made clothing for everyday use. People still use tailors to get suits made, I think.
Originally (going back to the '30s based on the ads I've seen), man-made fibers were proudly advertised for qualities such as "wrinkle resistance" or "lighter weight." And blending with natural fibers does help a lot. Those "Poplin" summer suits we Trads like were sometimes blends and they were fine (although, to me, the all-cotton ones "felt" better).
In the '70s, when I was a kid, "polyester" was viewed as cheap. For the next two decades, man-made fibers had a taint. But then, about 20 years ago, they started improving, I guess, especially for gym clothes and have made a comeback. Obviously, I'm oversimplifying, but you get the idea: even in my lifetime, the view of man-made fibers has changed a lot.